Numerous types of wireless communication devices are used throughout the world each day, including devices such as cellular phones, pagers, personal digital assistants (PDAs), and vehicle communication devices. Many of these devices use one or more types of communication channels, including voice and data channels, to provide a variety of services over wireless networks. Some devices utilize data encoding techniques to communicate both voice and data information over a voice channel, while other devices must use a data channel to send data information. In certain instances, the use of a dedicated data channel to send and receive data information can result in enhanced data services such as additional bandwidth, error detection, and inter-operability with other devices.
Some motor vehicles come equipped with onboard integrated wireless communication systems that are referred to herein as telematics units. Often times, owners of those motor vehicles choose to deactivate the cellular service associated with the telematics unit. Once the telematics unit is deactivated, normal cellular telephony service is not available to or from the vehicle. However, there are some instances in which it would be desirable to maintain some type of communication with the onboard communication equipment. More specifically, it would be useful even after the telematics unit has been deactivated to provide cellular communication between the motor vehicle and the call center in emergency situations, to enable the owner of the motor vehicle to reactivate the telephony service, and possibly to provide various services to the vehicle or occupants.